C 聊天程序收到错误分段错误(核心转储)

Question

我正在用C语言在客户端和服务器之间构建一个聊天程序。客户端将连接到服务器，向其发送消息。然后服务器将响应该meesage。

如果有另一个客户端连接到服务器，则新连接将创建一个新线程。所以我使用 pthread.h 用 C 语言构建了一个多线程聊天程序。请参阅下面的 server.c 和 client.c 代码以获取更多详细信息。

服务器.c

#include <pthread.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#define PORT 7778
void error(char *msg){
    perror(msg);
    exit(1);
}
void *clientHandler(void*);
int main(){
    printf("INFO enter the main()n");
    int sockfd, newsockfd, clilen;
    char buffer[256];
    struct sockaddr_in serv_addr, cli_addr;
    int n, threadID;
    pthread_t interrupt;
    printf("INFO before calling socket()n");
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
        printf("INFO after calling socket()n");
    if(sockfd < 0)
        error("ERROR opening socketn");
    printf("INFO before calling bzero()n");
    bzero((char*) &serv_addr, sizeof(serv_addr));
    printf("INFO after calling socket()n");
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = INADDR_ANY;
    serv_addr.sin_port = htons(PORT);
    printf("INFO after assigning Internet infon");
    if(bind(sockfd, (struct sockaddr*) &serv_addr, sizeof(serv_addr)) < 0)    
    {
        error("ERROR on bindingn");
        return 0;
    }
    printf("INFO before calling listen()n");
    listen(sockfd, 5);
    printf("INFO before entering While(1)n");
    while(1)
    {
        int re;
        clilen = sizeof(cli_addr);
        printf("INFO before calling accept()n");
        newsockfd = accept(sockfd, (struct sockaddr*)&cli_addr, &clilen);
        if(newsockfd < 0){
            error("ERROR on acceptingn");
            return 0;
        }
        printf("INFO before calling pthread_create()n");
        re = pthread_create(&interrupt, NULL, clientHandler, NULL);
        if(re){
            printf("ERROR return code from the pthread_create() is %dn", re);
        }       
    }
    printf("INFO before calling pthread_exit(NULL)n");
    pthread_exit(NULL);
    return 0;
}
void *clientHandler(void *param){
    int n, newsockfd;
    newsockfd = *((int*)param);
    char buffer[256];
    bzero(buffer, 256);
    while(1){
        n = read(newsockfd, buffer, 255);
        if(n < 0){
            error("ERROR reading from socketn");
            pthread_exit(NULL);
        }
        printf("Server received the message: %s", buffer);
        n = write(newsockfd, "Server got itn", 18);
        if(n < 0){
            error("ERROR writing to socketn");
            pthread_exit(NULL);
        }
    }
}

客户端.c

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#define PORT 7778
#define HOSTNAME "127.0.0.1"
void error(char*msg){
    perror(msg);
    exit(1);
}
int main(){
    int sockfd, n;
    struct sockaddr_in serv_addr;
    struct hostent* server;
    //char *hostname = "127.0.0.1";
    char buffer[256];
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if(sockfd < 0)
        error("ERROR opening socketn");
    server = gethostbyname(HOSTNAME);
    if(server == NULL){
        fprintf(stderr,"ERROR no such hostn");
        exit(0);
    }
    bzero((char*) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    bcopy((char*)server->h_addr, (char*)&serv_addr.sin_addr.s_addr, server->h_length);
    serv_addr.sin_port = htons(PORT);
    if(connect(sockfd, &serv_addr, sizeof(serv_addr)) < 0){
        error("ERROR connectingn");
        return 0;
    }
    while(1)
    {    
        printf("Please enter the message: ");
        bzero(buffer, 256);
        fgets(buffer, 255, stdin);
        n=write(sockfd, buffer, strlen(buffer));
        if(n < 0){
            error("ERROR reading from socketn");
            return 0;    
        }
        printf("[Server got it] %sn", buffer);
    }
    return 0;
}

好的，我使用终端在 Linux 环境中成功构建了 *.c 文件。

我使用这个命令行来构建 server.c

gcc server.c -o server.out -pthread

并使用这个来构建client.c

gcc client.c -o client.out

然后，我调用 server.out 来运行服务器：

 ./server.out

并运行客户端输出

./client.out 

但是，在我运行server.out时，我得到了错误：

Segmentation fault (core dumped)

伙计们，你能和我分享一下你对此的经验吗？我的代码在某个地方有问题吗？

Answer 1

此行将 NULL 作为处理程序的参数传递

 re = pthread_create(&interrupt, NULL, clientHandler, NULL);

它应该是：

 re = pthread_create(&interrupt, NULL, clientHandler, &newsockfd);

正如Sourav Ghosh评论的那样。

Answer 2

您需要将 newsockt id 传递给创建的新线程。

所以改变

    re = pthread_create(&interrupt, NULL, clientHandler, (void*)&newsockfd);

我在这里添加了第三个参数

---

使用 （void*） 进行类型转换不会给您一个警告:)